TeamSpeak is an application which allows its users to talk to each other over the internet and basically was designed to run in the background of online games. The voice quality and hereby the bandwidth usage is configurable and can be low for modem users or as good as normal phone calls for better connections. Still the client's maximum bandwidth won't exceed 25.9 KBit/s (=3.3 KB/s) upstream.
Also TeamSpeak uses as little latency as possible, which makes TeamSpeak one of the best online gaming communication programs.
TeamSpeak has a lot more features than these basics, but even unexperienced users don't have to be scared. As TeamSpeak is divided into a server and a client application, advanced users can set up a TeamSpeak server, which is so to say the meeting point for the clients. This means that beginners can just fire up the client, connect to a server and talk to their friends. After the first small steps they will discover a whole variety of features that give TeamSpeak a high rating when it comes to voice chat tools as well.

Friend Tracker & Server Browser
Instant Messaging While You Play
File Download System
Built-In Stats Tracking
Play With People You Know
Supports Over 250 Games And No Spyware

Popular game browser:
Supports all the popular games such as Counter-Strike, BF1942, Quake III Arena, etc.
Designed for what gamers want: fast and easy access to the game servers of their choice
Buddy tracker to find friends to play with
Filter wizard to create custom filters
Fast and efficient with NO ADWARE!
Plus many, many more great features...
Note: Trial version

IRC (Internet Relay Chat) is a virtual meeting place where people from all over the world can meet and talk; you'll find the whole diversity of human interests, ideas, and issues here, and you'll be able to participate in group discussions on one of the many thousands of IRC channels, on hundreds of IRC networks, or just talk in private to family or friends, wherever they are in the world.

NWNK-Irc is a full featured script and personal choice to many and is based on mIRC 6.01.

Qtracker is a free and new game server browser tool which helps you to find game servers for your favourite games as well as a built in buddy tracker.